[TowerTalk] US TOWER HDX-89 / Tash DX86 Wind Rating Differences

[TexasRF at aol.com]

Rich, wind speed and antenna loading are only two of the inputs to the  
engineering calculations. The biggest contributors are the tower section  
projected wind surface areas, They are related to leg and brace diameters and  
lengths.  Brace/leg angles have an effect as well. The calculations become  
quite tedious.
 
Then there are safety factors on top of that as well as the yield strength  
of the materials used. Different manufacturers use different safety factors 
and  grades of materials.
 
73,
 
Gerald K5GW
 
 
 
 
In a message dated 6/10/2017 9:01:21 A.M. Central Daylight Time,  
rthorne at rthorne.net writes:

This may  not be comparing apples to apples but here's my question after 
studying  the two towers.

US Tower HDX-89 claims 9.2 sq ft of max allowable  antenna wind area 90 
mph 3 second gust
Tash DX86  claims 21 sq ft  of max allowable antenna wind area 85 mph 3 
sec gust

After looking  at both designs they both start with a lower section that 
is 28.75" wide  and a top section that is 13 7/8" (Tash) and 13 15/16" 
(US  Tower)

So the designs appear to be the same, why are the allow able  antenna 
wind loads so different?  I realize that one is based on 90  mph the 
other on 85 mph.  Does the 5 mph delta add up to a 11.8 sq ft  difference?

Thanks in advance.

Rich -  N5ZC


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